Telecommunications network:
• Exchange of information in any form (voice, data, text, images, audio, video) over networks
• Any arrangement where a sender transmits a message to a receiver over a channel consisting of
some type of medium
Telecommunications network components
• Terminals: any input/output device that uses networks to transmit or receive data
• Telecommunications Processors: devices that support data transmission and reception
• Telecommunications Channels: media over which data are transmitted and received
• Telecommunications Control Software: programs that control telecommunications activities
– telecommunications monitors for mainframe,
– network operatings ystems for network servers,
– Web browsers for microcomputers.
Types of Telecommunications Networks
• Internet,
• intranet,
• extranet,
• wide area,
• Metropolitan Area,
• local area,
• client/server,
• peer-to-peer
The Internet: is a network made up of millions of smaller private networks, each with the ability to
operate independent of, and in harmony with, all the other millions of networks connected to the
Internet.
• No central computer system
• No governing body
• No one owns it
Internet Service Provider (ISP):
 A company that specializes in providing easy access to the Internet
 For a monthly fee, you get software, user name, password and access
An Intranet:
• A network inside an organization That uses Internet technologies (such as Web browsers and
servers, TCP/IP protocols, HTML, etc.) To provide an Internet-like environment within the
organization For information sharing, communications, collaboration and support of business
processes
• Protected by security measures such as passwords, encryption, and firewalls,Can be accessed by
authorized users through the Internet
An Extranet
• Network links that use Internet technologies To connect the Intranet of a business with its
customers, suppliers or other business partners
Wide Area Network (WAN): Telecommunications network that covers a large geographic area
Metropolitan Area Networks (MAN): a wide area network optimized a specific geographical area
• Such networks can range from several blocks of buildings to entire cities.
Local Area Network (LAN): Connect computers within a limited physical area such as an office,
classroom, or building
Virtual Private Networks (VPN): A secure intranets and extranets, that uses the Internet as its backbone
but relies on firewalls, encryption and other security
Client/Server networks: Clients (PCs or networked computers workstations) are Interconnected by LANs
and share application processing with network servers.
1. Clients: Provide user interface, perform some/most processing on an application.
2. Network Servers: Shared computation, application control, distributed databases.
Peer-to-peer networks: Networks that connect from one PC to another PC
Telecommunications Media (1. Wired Technologies, 2. Wireless Technologies)
• Wired Technologies (1. twisted-Pair Wire, 2. Coaxial Cable 3. Fiber Optics )
– Twisted-Pair Wire: the most widely used medium for telecommunications.
– Coaxial Cable
– Fiber Optics: can conduct pulses of visible light elements
• Wireless Technologies: rely on radio wave, microwave, infrared, and visible light pulses
– Terrestrial Microwave
– Communications Satellites
– Cellular Systems
– Wireless LANs (WiFi)
– Bluetooth
Telecommunications Processors
• Modems: Convert digital signals from a computer into Analog frequencies that can be
transmitted over ordinary telephone lines.
• Internetwork Processors (1.Hub 2.Switch 3.Router 4.Gateway)
– Hub and Switch : port switching communications processors that make connections
between different network devices (computers, other processors, etc.)
– Router and Gateway – intelligent communications processors that interconnects
networks based on different protocols and different communications architectures
• Multiplexers: Allows a single communications channel to carry simultaneous data transmissions
from many terminals
Protocol: standard set of rules and procedures for the control of communications in a network
Network model: is that the process of communication between two endpoints in a telecommunication
network can be divided into layers, with each layer adding its own set of special, related functions.
• Two main type of Network Model:
– OSI model
– TCP/IP model
Bandwidth
• Frequency range of a telecommunications channel
• Determines transmission rate (speed) and represents the capacity of the connection.
• measured in bits per second (bps)